Headlight



O. WINSTON.

HEADLIGHT.

APPLICATlON mm mm. 9. 1911 Patented Oct. 28, 1919;

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' HEADLIGHT.

Specification of Letters Pll-tcnt. P t t d Oct. 28, 1919'.

Application flied March '9, 1817. Serial H0. 153,589.

to be a full, clear, and exert description 0 the invention, such as will enable others skilled in the art to which it. appertains to make and use the same.

My present invention relates to headlights and is p:. -ticularly directed to the provision of an improved form of lens and to an improvedrelative arrangement thereof, in respect ton concave reflector and electric light source withinthe latter.

In the accompanying drawings which illustrate the invention,.likc characters indicate like parts throughout the several gviews.

Referring to the drawings;

Figure 1 is a vertical section showing a headlight en'ibodying my invention and wherein a two-filament light bulb is cm ployed as a means for shifting the light source from the axis of the reflector to .1 point vertically above said axis:

Fig. 2 is an elevation looking at the inner face of the lens;

Fig. 3 is a fragmentary view in inner face elevation showing, on an enlarged scale, one of the prismatic sections of the lens;

Fig. 4 is a section on the line -'l-4 of Figs. 2 and 3;

Figs. 5 to 15, inclusive, are sections taken on the correspondingly marked section lines on Fig. 3; l

Fig. 10 is an enlargement of the prismatic section shown in Fig. 10 and indicating the travel of the ray of light in passing thereto. themthrough and therefrom: and

Fig. 16 is a view corresponding to Fig. l but showing a headlight having asingle filament light bulb.

0f the parts of the headlight. the numeral 17 indicates the casing. the numeral 18 the clamping ring thereof. the mnm-ral 19 the bulb 20 prog'fcts and held by a suitable support. T is bulb support, so far as this invention is concerned, may be of any sultable construction, but as shown, com uses a shank engagin sleeve 22 and a. tu ular socket 23 screw into a. flanged hub 24secured to the back of the reflector.-

The bulb shown in Fig. 1, is a two-filament bulb, the one filament havin spot at a and the other having its 01: spot at II. The point a is at the axis of the reflector and preferably, also, at the focal center thereof. The

above the axis of the reflector. By means includes a battery 28, and switches 29 and 30, either of the two filaments a and b may, atwilhbe energized and used as the light source of the headlight.

In the headlight illustrated in Fig,,16 the light bulb 20 is provided with a single filament 0, the hot spot of which is at the axis of the reflector and preferably also at the local center thereof. This filament is conuected to a battery or source of electrical energy 31, by leads 32, in one of which is a switch 33.

We will not consider the novel construction of the lens, the preferred form of which is illustrated in the drawings and which, described in detail, is as follows;

One face of the lens, preferably its inner face, is formed with prismatic surfaces that extend horizontally across that face of the lens. The beveled. surface of all of the prisms diverge downwardly from the plane of the lens, but the different prisms have a different bevel.

The prisms having the greatest maximum hovel are approximately at a horizontal line preferably in a constant order of succession.

For example, with the variation in the maximum hovel of the successive prisms may be as indicated by the small numerals marked on the curved line in Fig. 2, by reference to point b is vertically its hot o the plane of the lens and the egree to bevel of the prismsiabove the horizontal central line infimase in a downward direction one degree, eah over the other, while the prisms that are'below the said horizontal line rogressively decrease in a downward direction.

Each bevelhas a maximum be'vel at points midway 'betw'een its extremities and its longitudinal center. In Fig. 2, theap roxlmate points of maximum bevel are indicated by the points where the small numerals are marked thereon, and in'directions, both to the right and left of these points, the stud prisms have progressively decreasing bevel, arrangement, the bevel and in the preferred diminishes to zero at the latter extremities of the said prisms, and at points on a vertical line that intersects the axis of the lens. Instead of diminishing to zero at points stated, the said bevels might diminish to an angle of less than an les of the said ith the above the respective maximum prisms.

nearest to the horizontal line intersecting the axis of the lens give the greatest downward deflection to the light rays', but in any particular prism the greatest deflection of the light roduoed therebywill be from points mi way between its extremities and a line that intersects the said prisms and the axis of the lens. This gives a general downward dcfiection of the light beams with a minimum downward deflection from the extremities of the prisms and from the central portions of the prisms and a maximum downward rlefiection oncurved lines thatintersect the prisms midway between their extremities and the said vertical central line.

In Fig. 1 the lighter ray lines indicate the light rays when the light source is at a, and the heavier ray lines the rays when the light source is at the vertically ofi'set point 6. It will thus be observed that-the light beam is given a greater downward deflection when the light source is at 6 ,than when the light source is at a.

Obviously, the best light beam for country road drivingis' produced when the light source is'at a and the best light beam for city .street driving is produced when the ight source is at b. It; is not desirable to give this great downward deflection to the is given to the more intense rays from the'back of the reflector. Itis desirable to get a maximum amount of intense rays on the road, but it is also desirable difi'use some of the less intense light rays so as to l1ght up objects above the road and at the sldes of the road, and for this reason,

, of t described arrangement,

- general direction, said prisms,

the prisms nearest tothe horizontal plane of the axis of therefl bevel and those nearest the top and preferably also those nearest the bottom are given decreased or less le.' V i In the use of a headlight with an ordlnary reflector adjusted so as to throw approximately the lower half of the light beam upon the ground, which lsquite a common arran ment, the lower half of the light beam w l "be distributed over many hundreds of square feet of road surface, and

er unit of surface, the road will begiven ut a vet small percentage of light, as

- compared withthe amount of light thrown upon a vertical object in the road, by the upper half of the light beam. This is a result just reverse from that'desired. ideal arran inent would be one in which there woul be at least as much light, per unit of surface, thrown upon the road, as there would be upon a vertical object above 'the road; and such an arrangement, obviouslv, requires .very much the greater part he light beam to be distributed on the ound and a very minor part of the light In to be difl'used above the road. This ideal result is.cl0sel approximated by the use of the improved lens above described, which, as already stated, roduces very great downward deflection o the more intense rays of the light beam and difluses some, or a minorpart of the less intense light rays above the road. Wh iitlI clagn ilsl: -h h I 1.. ens readlitsavlng' a up of parallel prisms beveled in the same g em eral direction, said prisms, individually, having maximum bevel at points intermediate of the rim of the, lens and a diameter' thereof perpendicular to the edges of said prisms and having decreasing bevels progressively in both directions from the respective points of maximum bevel.

2. A lens for headlights having a group of parallel prisms beveled in the same gem eral direction, and among themselves, in a circumferential direction, having, ro sively varying bevels, said prisms, 1nd1vidually, hav ng maximum bevel at points intermediate of the rim' of the lens, and a diameter thereof perpendicular to the edges of said prisms, and having decreasing bevels progressively in both directions from the respective points of maximum,bevel. a

3. A lens for headlights having ,'a group of horizontalprisms beveled inthe same individually, having maximum "bevel at points intermediate oftherim and the vertical; diameter of said lens, and having decreasing bevels' progressively in both directions from the re-,. spective points of maximum bevel;

4. A lens for headlights having a group of horizbptaLprism; beveled in the same ward the'lower portion of the lens having In general dlrcctlon, sald prisms, individpally, progressively invrmming bevel. having maximum bevel at points mter- In testimony whcl'uui I affix my signature .gnudiate of they rim and the vertical diamin presence of two witnesses.

cter of said lens and having decreasing Y r lmvcls pmgressivefy in both directions frmn I OVLRTON the respective points pf maximum bevel the WItDESSGS: suirl prisms, among themselves, m a duec- BERNICE G. WHEELER, tirm cirvnmferentially from the upper bo- HARRY D. .Klmonn. 

